They already have equal rights. All men – whether straight or gay – are free to marry women. All women – whether straight or lesbian – are free to marry men. That's absolute equality.

Homosexuals want additional rights, and I'm willing to support them.

Theoretically, if gay marriage is universally allowed, wouldn't straight people then be able to be "gay-married" as well? It's not like they require you to prove your gayness beforehand. By your logic, equality would be preserved exactly.